/*
int
parse '$1' 1
parse '¢2' 2
parse '£2' 2
parse '€3' 3
parse '￡3' 3
parse '𝄞4' 4
noparse x Amount 2
*/

/* The above symbols include 1, 2, 3, and 4-byte UTF-8 encodings. */
S :: int ← Currency a:Amount → a
Amount ← [0-9] { *ref_ptr(ref()) - '0' }
Currency :: void ← .
